Electronic devices today are ubiquitous, and portable device are often carried with people everywhere they go. While these devices have changed the way people interact and conduct business, they can easily become a nuisance. For example, a user of a mobile phone may intentionally, or unintentionally, leave the ringer of the phone on. This may lead to the phone ringing loudly at an awkward or unwanted time. Some phones allow a user to silence or stop a ringtone by pressing a button on the phone, but the button may not be easily or quickly accessible.
It has long been known that the natural processes of the human body create a perpetual low-frequency vibration. Sensing of human vibrations, or tremors, has been used, for example, in surgical instruments to mitigate the effect of hands shaking. And while human tremor detection has been proposed for use with cellular phones, prior techniques do not provide an overly accurate detection method. For example, a phone intending to detect tremors while being held in a human hand would return a false positive every time the phone was placed in a pants pocket, near a leg that emits the same natural tremors.